Blake Ferguson appeals his conviction

Fallen NRL star Blake Ferguson has argued he grabbed the crotch of a woman in a Southern Sydney bar, believing it to be someone else, in an appeal to quash an indecent assault conviction that has halted his career.

The 24-year-old was found guilty in December last year of indecently assaulting a woman during a night out at Cronulla's 2230 Bar, where he was celebrating his NSW Origin selection with teammate Josh Dugan.

He was handed a two year good behaviour bond and deregistered from the NRL following the conviction.

On Wednesday Greg James QC argued Ferguson had an honest belief that the woman he touched would be receptive to his advances because he thought she was a girl he had spent time with earlier on night in question at Northies in Cronulla.